Selective drop end door balancer



United States Patent Inventor Orville Ingram Toledo, Ohio Appl. No.616,017

Filed Feb. 14, 1967 Patented Nov. 10, 1970 Assignee By mesne assignmentsto Midland-Ross Corporation, Cleveland, Ohio, a corporation of OhioSELECTIVE DROP END DOOR BALANCER 10 Claims, 7 Drawing Figs.

US. Cl .1 105/406 Int. Cl .1 B6ld17/00, 861d 25/00 Field ofSearch105/410,

[56] References Cited UNITED STATES PATENTS 2,167,427 7/1939 Tatum .t2,505,290 4/1950 Ingram 2,769,406 11/1956 Goodninu. 3,022,536 2/1962Floehr Primary Examiner-Arthur L. La Point Assistant Exam iner-RichardA. Bertsch AnorneyWilmer Mechlin ABSTRACT: A balancer for assisting inclosing a drop end door, using both main and compensating torsionsprings, the former acting over the full range of movement ofthe doorand the latter over only part of that range.

Patented;Nov. 10,19 70 I 3,538,858

Sheet 1 of 3 FIGZ Inventor: Orville Ingram By MJWM his AHorney PatentedNov. 10, 1970 3,588,858

FIG.3 I Inventor:

Orville Ingram his AHorney SELECTIVE DROP END DOOR BALANCER BACKGROUNDOF THE INVENTION Railway gondola cars having drop end doors that arehinged at the bottom and in opening swing inwardly to a substantiallyhorizontal position along the floor, often have each door equipped witha door balancer providing a spring force for assisting in closing andcushioning opening. Heretofore, such doors at maximum have been about 3feet high and 600 pounds in weight and for such a door a balancer of thetype disclosed in Goodwin U.S. Pat. No. 2,580,760, issued Jan. l, 1952,is entirely practical. However, to meet the demands of railroads andshippers for freight cars of increased capacity, gondola cars have nowbeen designed with oversize drop end doors as high as 6 feet andweighing as much as 1,450 pounds.

A conventional door balancer may have one or more springs, {usually rodsor coils in torsion, and, invariably, each spring acts to resist openingor assist closing movement of the door over the full range between openand closed positions. Attempts to adapt such balancers to oversize doorsby increasing their spring force have not been successful, thedifficulty, it has now been determined, being the too great variationbetween the straight line force plot or curve of the torsion springs andthe sine load curve of the oversize door in swinging between closed andopen positions.

SUMMARY OF THE INVENTION The improved door balancer of the presentinvention provides an effective load balance for even oversize doors byusing full range main and part range compensating springs whichcooperate to hold within acceptable limits the force required at anypoint in closing the door. In its preferred form the improved balanceruses torsion springs and enables the forces exerted by each and therelative ranges of their actions to be selected to suit end doors of anygiven size. The preferred balancer also is installable as a unit withthe door, has its springs enclosed to protect them against the elementsand during assembly is adjustable to compensate for manufacturing orassembly tolerances or other special requirements of a particularinstallation.

With the foregoing its principal objectives, other objects andadvantages of the invention will appear hereinaftern the detaileddescription, be particularly pointed out in the appended claims, and beillustrated in the accompanying drawings, in which:

FIGURE DESCRIPTION along lines 6-6 of FIG. 4; and

FIG. 7 is a graph showing the relation between the load curve of atypical oversize door and the torque curve of a balancer of thisinvention.

DETAILED DESCRIPTION Referring now in detail to the drawings in whichlike referenced characters designate like parts, the improved gondolacar end door balancer of the present invention, while applicable to enddoors of smaller size, is particularly designed for the recentlyproposed oversize doors. In either case, the door, designated as I, willbe one of a pair at opposite ends of the body, indicated at 2, of thegondola car (not otherwise shown).

As customary, the illustrated door I is mounted on and between theadjoining corner posts 3 at the corners of the body 2 at its end' of thecar for pivoting, hinging or swinging about a horizontal axis extendinglaterally of the body adjacent the door's bottom 4 and swings or movesfrom a vertical position in which it is stopped by engagement of itsfront or front faces 5 with instanding flanges 6 on the corner posts, toa substantially horizontal position in which it lies along the body'sfloor 8.

As does the balancer of the Goodwin patent, the improved balancer 9itself preferably provides the pivotal mounting by including a pair oflaterally spaced body brackets 10 at opposite sides of the door, each ofwhich is fixed, as by riveting, to and instands laterally from one ofthe corner posts 3. The body brackets 10 are laterally aligned and eachpivotally mounts one of a pair of laterally spaced and aligned doorbrackets 11 fixed or secured to or rigid with and at opposite sides ofthe door 1. In the preferred pivotal mounting each door bracket II has atubular part I2 forming a bottom or lower corner of the door and a platepart 13 which is fixed to or rigid with the tubular part and throughwhich the bracket is riveted or otherwise fixed to or made rigid withthe overlying body portion 14 of the door. The tubular part 12 of eachdoor bracket 11 has in an outer end portion 15 a cylindrical aperture oropening 16 in which is journaled or rotatably received or seated acorrespondingly cylindrical hollow trunnion or boss 17 on and integralor rigid with and instanding from the adjoining body bracket 10.Concentric or coaxial, the bosses I7 and tubular parts I2 of the bodyand door brackets together provide a bottom hinge for the door and fixthe laterally extending, horizontal axis on which the door swings ormoves between closed and open positions.

In addition to being the door butts or parts of the hinge on which thedoor I swings, the door brackets 11 in the preferred embodiment also arethe opposite end sections of a spring housing 18, extending laterallyacross the bottom 4 of the door. If, as disclosed, the center section I9of the housing 18 between and connecting the tubular parts 12 of thedoor brackets 11, is a pipe or tube section of appropriate length anddiameter, fixed or secured as by welding to the overlying body portion14 of the door, the tubular parts may have on their inner end portions20 instanding annular or cylindrical flanges 21 telescoped into orreceived in the outer ends of the center section.

The improved balancer 9 depends for assisting an operator in lifting thedoor 1 to closed position upon a main or primary spring or spring 'group22 and one or more compensating, secondary or auxiliary springs orspring units 23. At least the main and preferably all of the pluralityof springs are torsion springs. The main spring or group 22 is intendedto act over the full range of movement of the door, while the purpose ofthe compensating spring or springs 23 is to compensate for thedifferences between the straight line torque plot or curve of the mainspring 22 and the sine load, force or torque curve of the door, so as toreduce the effort or force required to be exerted by an operator at anypoint in closing the door, with the reduction preferably sufficient toenable the door to be closed by a single operator. The preferred mainspring 22 is a plural or, for an oversize door, multiplate torsion barwhich is anchored at opposite ends or other spaced points to the body 2and the door I and acts throughout the movement of the door betweenclosed and open positions, storing energy or being energized as the dooris opened and, on subsequent closing, restoring or releasing that energyor torsional force to assist the operator.

Conveniently housed or contained in and extending longitudinally of thehousing 18 substantially on or along the doors hinging axis, thetorsionbar 22 may extend through the housing with one end suitably anchored tothe car body and the other tothe door, as do the torsion bars in theequalizer of Ingram U.S. Pat. No. 2,567,287, issued Sept. ll, I951, butpreferably follows the Goodwin patent in being divided substantially atthe longitudinal center of the housing into two half springs 24. Each ofthe preferred half springs extends through its half of the center pipesection 19, the tubular part 12 of the adjoining door bracket 11 and thehollow trunnion 17 of the cooperating or adjoining body bracket and hasits outer end anchored in a fixed anchor 25 in the body bracket in theform of a generally rectangular slot in that bracket at the outer end ofand centered radially on the trunnion. The opposite or inner ends of thehalf springs 24 are received or anchored in opposed or oppositelyfacing, generally rectangular seats or slots 26 in a center or dooranchor or anchor member 27. Initially rotatably mounted in the centersection 19 of the housing 18, the anchor member 27 has a radial leg 28extending through an initially open radial slot 29 in the housing forenabling the member to be rotated during assembly to adjust or set thetorsion of the main spring 22 in the closed position of the door atwhatever value is desired. The anchor member is then welded in place orotherwise fixed to the door to hold or maintain this value when the dooris closed and as the door or moving anchor apply to or receive from themain torsion spring 22 a torsional or twisting force over the range ofmovement of the door between closed and open positions.

The force or torque required in the absence of a spring assist forlifting the door 1 through approximately 90 from its substantiallyhorizontal open position to its vertical closed position, willprogressively decrease from a maximum at open position to zero at closedposition, with the maximum determined by the weight and height of thedoor. As mentioned earlier, this progressive decrease follows a sinecurve, while the energy or torque output of an energized or torsionedtorsion spring decreases at a fixed rate and therefore follows astraight line. Consequently, any arrangement of torsion springs, inwhich all act in the usual way throughout the range of movement of thedoor between open and closed positions, can match in its availabletorque the force or torque required to lift the door at most at only twopoints and elsewhere in the range of movement the available and requiredtorque will differ to a greater or lesser degree. lt is this variancebetween the lifting force required on the door and the force derivablefrom one or more torsion springs so acting over the range of movement ofthe door from open to closed position, that disenables such springs fromeffectively assisting in closing an oversize drop end door. However, theenergy derivable from a plurality of torsion springs can be an effectiveassist in closing even an oversize door if, in accordance with thisinvention, one or more act over the full range of movement of the door,while another or others, by acting over a lesser range, compensate atleast partly for the differences within that range between the requiredforce and the force derivable from the full range spring or springs.

With the main torsion spring or bar 22 the full range spring, thepreferred balancer has as its part or partial range compensating spring23 one or a pair of coil springs acting in torsion and encircling themain spring and substantially centered therewith on the doors hingingaxis. Each such compensating spring suitably is housed in the tubularpart 12 of one of the door brackets 11 with an inner end 30 in the innerend portion 20 of that part and lockable or holdable against and limitedin movement relative thereto in an uncoiling or energy releasingdirection by a radially instanding stop or shoulder 31 on that portion.The opposite or outer end 32 of the coil spring 23 is received in theouter end portion of its door bracket and engageable for limiting itsturning or movement relative to the end portion in an uncoiling ortorque-releasing direction by a radially instanding stop, stop lug,shoulder or abutment in that end portion and facing oppositely from theradially instanding limit stop or stop shoulder 31 in the inner endportion 20. The springs outer end 32 is so bent or formed as to lie orbe disposed in the path of rotary movement relative to the door bracket11 ofa body or power lug 34 fixed to or rigid with and radiallyoutstanding from the boss 34 on the adjoining body bracket 10. Whileboth the door stop lug 33 and the body lug 34 project or extend radiallyinto the annular space 35 between the boss 17 and the side wall 36 ofthe outer end portion 15 and from opposite directions, the body lug ispositioned radially inwardly of the door lug so that the lugs are clearor free to pass each other. On the other hand, both of these lugs, byextending into the portion of the space 35 occupied by the outer end 32of the compensating spring 23, are disposed in the path of andengageable with that end when presented thereto. Contained afterassembly within or inside the tubular part 12 of the related doorbracket 11, the body lug 34 is insertable thereinto by appropriateradial slotting of the end wall 37 of the outer portion 15 about thetrunnionreceiving aperture 16.

When the balancer is operating in service, the outer and inner endportions 15 and 20 of the tubular part 12 of each door bracket 11 arefixed to the door for turning or swinging therewith relative to theadjoining body bracket 10. However, whether so fixed by welding or othersuitable means, the end portions 15 and 20, if the bracket is to house acompensating spring 23, initially are rotatable relative to the partscenter or midportion 38, which, in addition to being interposed betweenand axially spacing the end portions, is integral or rigid with theplate part 13 of the door bracket 11 through which the latter is fixedto the body portion 14 of the door. lt is this initial relativerotatability of the end portions that is employed to preor selectivelyset the torque or torsion of the compensating spring 23, asv well as topredetermine or selectively set the partial interval or range within thefull range of movement of the door between closed and open positionsover which the compensating spring is active.

Turning of the end portions 15 and 20 oppositely in the coilingdirection of the coil spring 23 to the point atwhich each of the stops31 and 33 just engages the related of the ends 30 and 32 of the springwill leave the spring free, but by further opposite turning of the endportions in the same direction the spring can be torsioned or energizedto any desired extent. This torsioning alone affects nothing but thespring when the end portions are locked in place since they are both onand part of the door 1. However, if, after their relative rotation toapply a predetermined or selected normal or initial torsion or torque tothe spring and with the door in its vertical closed position, the endportions 15 and 20 are turned or rotated in unison relative to theadjoining body bracket 10 to a point at which the stop lug 33 on theouter end portion is in advance in a door opening direction of the powerlug 34 on the body boss 17, the are or angle between or relativeangularity of the lugs will be that of the lost motion or delay throughwhich the door can swing in opening without bringing the compensatingspring into action. Consequently, by rotating the end portions 15 and 20relative to each other and the adjoining boss 17 before welding orotherwise fixing those sections to the center section 38 of the doorbracket, it is possible to preset or predetermine both the initial ornormal torsion or torque of the compensating spring 23 and the partialrange within the full range of movement of the door over which thespring acts or is operative. lf, instead of a single compensating spring23, two are employed, one in the door bracket part 12 at each end of thehousing 18, the individual adjustment derivable from the initialrotatability of the end portions 15 and 20 of the two door bracketsenables the preset torsions of the springs and the partial ranges overwhich they act to be the same or different, as desired.

The effect of compensating springing in reducing over the range ofmovement of the door the difference at critical points between thetorque required for equilibrium with the load of the door and thatobtainable from springing acting over the full range of movement of thedoor, is exemplified in the graph of P10. 7. In that graph, the sinecurve of the door load or torque required for equilibrium at any pointin the range of movement of a 6 feet, 1,450 pound drop end door, hasbeen plotted against the composite stepped torque curve produced by afull range main torsion spring without preset and a pair of pretorsionedcompensating springs preset to act over different ranges.

Whether or not any of the main'and compensating springs 22 and 23 ispretorsioned, each will be energized over its range of action as thedoor is opened and release its stored energy over the same range in aclosing operation. As in the graph of FIG. 7, the force of gravity onthe door, once it is moved from its vertical closed position, maysuffice alone to energize the springs, although it is entirely possiblethat in some installations it may be found desirable to supplement theforce of gravity by a force applied by the operator at some pointsduring opening in order to decrease the maximum effort required to beexerted by him in closing the door. In any case, the springs will assistclosing and, in being energized during and consequently resistingopening of the door, will cushion opening.

From the above detailed description it will be apparent that there hasbeen provided an improved balancer for drop end doors of railway gondolacars, which, by using both full range main and part range compensatingsprings, effectively assists closing of even an oversize door and isadjustable during assembly for selective action of its one or morecompensating springs to suit particular installations. It should beunderstood that the described and disclosed embodiment is merelyexemplary of the invention and that all modifications are intended to beincluded that do not depart from the spirit of the invention and theappended claims.

lclaim:

1. A door balancer for a drop end door hinged between sides of a body ofa railway gondola car for movement between a vertical closed positionand a substantially horizontal open position, comprising main torsionspring means acting between the door and the body over the full range ofmovement of the door between closed and open positions, compensatingspring means acting between the door and the body, and means forlimiting the action of said compensating spring means to a part ofsaidfull range.

2. A door balancer according to claim 1, wherein the compensating springmeans are torsion spring means.

3. A door balancer according to claim 2, wherein the main andcompensating spring means resist and are energized in opening andrelease energy and assist in closing of the door.

4. A door balancer according to claim 3, wherein the main spring meansis a torsion bar, the compensating-spring means are coil spring means intorsion, and the main and compensating spring means extend along and aresubstantially centered on the hinging axis of the door.

5. A door balancer according to claim 3, wherein the limiting means isselectively adjustable prior to service operation for varying thepartial range of action of any of the compensating spring means.

6. A door balancer according to claim 3, wherein the limiting means isselectively adjustable prior to service operation for varying both thepartial range of action and the normal torsion of any of thecompensating spring means.

7. A door balancer according to claim 4, wherein the torsion bar extendsthrough and the compensating spring means are contained in a housingfixed to and extending across the bottom of the door.

8. A door balancer according to claim 7, wherein the door is hinged tothe car body by a pair of door brackets rigid with and at lower cornersof the door and each having a part journaling a trunnion rigid with andinstanding laterally from a body bracket fixed to an adjoining side ofthe body, said door bracket parts form end sections of the housing, andat least one of said parts houses a compensating coil spring.

9. A door balancer according to claim 8, wherein the part of each doorbracket housing a compensating coil spring includes initially relativelyrotatable outer and inner end portions each receivinga corresponding endof the coil spring, and stop means in said end portions and eachlimiting turning of the spring end therein in an uncoiling directionrelative thereto for enabling the torsion of the spring to beselectively preset by relative rotation of said end portions prior tofixing thereof to the doorbracket.

10. A door balancer according to claim 9, including for each doorbracket part housing a compensating coil spring a radially outstandinglug on the trunnion journaled in the outer end portion of the part, saidlug being disposed radially inwardly of the stop means and in the pathof the spring end in said outer end portion for energizing and receivingenergy from the spring respectively on opening and closing of the doorover a range predetermined by the relative angular dispositions in whichthe lug and stop means are selectively set in the closed position of thedoor.

